MOSCOW, Russia - Russia's security service on Thursday said it foiled an attack on a ship in the Black Sea, where tensions are building after the end of a deal protecting grain exports. The FSB said it "foiled an attempt by Ukraine's special service to commit a terror attack aboard one of the Black Sea Fleet ships carrying high-precision missile weapons". It detained "a Russian navy serviceman who had been recruited by the Ukrainian special service" and was carrying two improvised explosive devices, a statement said. The serviceman is suspected of "terrorist attack", trafficking explosives, treason and disclosing state secrets, according to the FSB. Russia's Black Sea Fleet has been repeatedly targeted since the beginning of Moscow's military campaign in Ukraine more than a year ago, but attacks have increased in recent weeks. On Tuesday Russia said it repelled a drone attack on a military patrol boat deployed southwest of Sevastopol on the annexed Crimea peninsula. Drones last week damaged Russia's Crimea bridge, a key military supply artery from mainland Russia to the peninsula. Ukraine claimed the attack.